Piezo-electric crystal control system



4 1931. A. HUND 1,788,239

PIEZO ELECTRIC CRYSTAL CONTROL SYSTEM Filed May 12, 1927 Alla-a1- IN V EN TOR.

A zzyasf 1] mm,

Patented Jan. 6,- 1931 ITED- JSTQAFITES AUGUST FUND, on BETH'ESDA, l MaBYnAivD, Assr'duoie, "BYglVIESN'E AS IGN ENTS, "r

FEDERAL TELEGRAPH coMrAivY, A CORPORATION or CALIFORNIA rmm-ELEcr-n-Io enYsr "coivriaotsrsmnm Application filed. May 12-, .1927; Teena-1m. 190 ,8845

My invention, relates broadly to piezo electric, controlled oscillator circuits,v and i more particularly to a piezo electric; crystal c0ntrolled oscillator "system having meansf tor stabilizing" the ioperation of the oscillation system and preventing :reactionary effects upon theipiezoelectriccrystalgelenient. V I g One of the objects aof: ,my invention is y to provide apiezolelectric crystal oscillator sys- 10 teni with a branch circuit connected, there- With forsustainingoscillations independent 11y of the 1electronltube oscillator system and preventing reactionary effects upon the piezo electric crystal element for stabilizing the r 15 operationofrthe oscillation. system. v

. Another object of my invention is vide a circuit arrangement for apiezo electric crystal-.oscillatorsystem in which the effects of the circuit oscillations with respect to the piezo electric-crystal element'maybereduced to I a kminimum aandcihigh frequency oscillations sustained with .sa-high, degree of. sta bility. 1 1 1 Other .anclwfurtherobjects of myinvention residein thecircuit-arrangement of the lpiezo electric crystal oscillaton system as more/fully set 't'orthein fithe specification hereinafter following :by I deference {to the accompanying drawings in which: I I

a i .Eigure .lillustrates oneifor n .of,circuitqarrangeinentlof the piezo el ectriccrystal oscile 'lator .systemmf my inventiony 2,,i'lluscrystaloscillator system ofimy invention. 1 In sustaining theioscillations Of the ipiezo "electriccrystal-elemntsflby meansrof 3-1511 elec r tube oscillator circuit, the inherentoscilla tions existent :in the (GlEiCliI'OIl, tube {system ;by virtue?ot the;coupling between theicircuits of electric crystal element thus interiering with the: stability ofzthepiezo electric crystal controlledcircuitszandcausing ashift inthefrethe 1.eleotron,;tubc have; a; ten encyrz-to reactwith the oscillations generated by theipie'zo c ferred. The ioscillations in the loiad ibranch are thus removed from the oscillation, generatorj n such nanner that reactionary. effects upon the ;piezo electric crystal element are substantiallyreduced and interference 'between the load branch and the oscillation generation circuit substantially eliminated.

Referring to the drawings in detail-1 reference character 1 'designatesrani electron; tube arranged; in, a circuit for sustaining the ,osc llations 7 ofv ja-piezo electric r crystal element: Reference-character 2 designatesan electron lube which is arranged in a branch-circuit withres'pect to theelectronrtube=1 foncontrol ofthe osc'illations generated inthe circuits of V.

electron tube 1 without reactionary effects of 4 the osc llations upon the piezo electric crystalsystenn The electron tube.- 1 includes cathode 14;; grid electrodeQlband plateielec trode 1c. The electron tube 2 includes cathode 2a,;grid electrode 2?) and 'iplatelelectr'ode 2c." The cathodes laandflafarelheated yfrom a p owersour'ce designated at .3. The outpu't circuits :for each ,oflthe tubes include/1a, Source of.-potential4. The electron tube 1 is represented ashaving an input-circuit 5 an dlan output circuit 6.; The inputcircuit?) includes a biasing battery, 8:;and a. controlling mesistor 7. ;Theoutput-circuit 6-;includes a parallel branch circuit 3 consisting [of inductance 1-1 shunted @by tuningvcondenser 10.;1) The piezo electric -cry stal {element which controls the circuits of electron tube'fl is; designatedat 12 positionedbetweenelectrodes'1 land 15. a The c electrode 1 maybe connected with the plate electrode zlc'as l represented Fig. :1,;Whi le the electrode 15 is connected with the grid electrode 1?) whereby constant frequency "cur- I rents existentacross the piezo I electric'jcrystalj element 12 are impressed upon the circuits ofthe electron tube 1-.=fThe .electron tube 2 has itsainp'ut terminals tha-t is'fgrid, electrode 1 7 2b and filament electrode 2a,; connected in shunt vvith the input terminals of theele'ctron tube 1. V Theoutput circuit of electron tube-2 I 'is completed from plate electrode2c-through the primary winding-of transformer system 20 to high potential source 4 back to the cathode circuit. Inasmuchas grid electrodes 1b and.2b=areiconnectedtogetherany variations existent on; grid-1b would .ialso existomgnd 2?) and would be greatly amplified in the output branch ofthe electrode tube 2.

16 having contact" 160 and 16?) by which the piezo electric crystal element 12 may. be connected selectively across the input electrodes or across the grid and the anode of tube 1. I

have found that the starting of oscillations may befacilitated in theelectron 'tubecin cuits when the iezo electric crystal is connectable at will, either across the grid and filament electrodes or acrossthe plate and desired work circuit.

filament electrodes. 1 have designated tube 2 having its grid electrode QbicapacitiVely connected with the grid electrode 11) through the capacity coupling device 17. order to control the operation'of electron tube 2 the input cir'cuit'tliereof may be bridged by the biasing battery 19 andthe control resistor 1 8; The transformer system 20 conveys the oscillations from the load branch to any 'The load branchconstituted by electron tube2 has itsinput circuitincomm'on with therefore'transferred to the" load circuit in the input circuit of electron tube 1,,and the same source of power is used for heating the cathode'and impressing the proper operating potential upon the anode as -exists in thecir -v cuits of electron tube 1. Byseparating the load branch from the oscillation generation circuit variations which might exist in the load branch wouldnot necessarily afiect'the operation of the oscillator circuit, For exramplegfa change in the electron tube 2 would have substantiallynoefiect upon'thefrequency of oscillations developed in'the ci'r cuitsof electron tube 1. However, such a change occurring in the circuits of the electron tube -1 would substantially shift the frequency. The'oscillations which' aresustained by the piezo electric crystal element 12 are eluding ele'c'trontube 2 in'such manner that reactionary efi'ects upon the piezoelectric crystal element 1;2 are substantially prevented.

By reason ofthe separation of the oscillation generation circuit from the loadcircuit, a

high degree of -'stab'ility" in operation of the oscillation-circuit is obtained and the effects if-variations in the loadfprevent it"from influencing the'character of the oscillations infthe high'trequency gen'erator'circuitfi My}invention has been found to be highly practical and-elficient in operation, and while 'l I have described the"circuit arrangements of my nvention'in preferredembodiments;I deg sire that it be'understood that modifications maybe made'andth'atno limitationsupon my invention are" intended other thaniareimf posed by the scope of theappendedfclaims; V lVhat I'claim as new and desire to secure by vLetters Patent of the United States? is as follows'z"; j V v 1; A piezoelectric crystal' controlsystem,

comprising" an electron :tube having grid,

'nectingsaidpiezo electric crystal element in cathode and plate'electrodes, input'and output circuits interconnecting saidelectrodes, a In Fig. 2 I have shown a switching system piezo electric crystal element, switching means for connecting sald piezo electric crystal elementacross said grid and cathode electrodes or across said grid and plate electrodes,.said circuits being arranged to su s tam the oscillatlons of said piezo electric crystal element, an auxiliaryelectron tube system and means connecting the input circuit of said auxiliary electron tube system with theinput circuitof said first mentioned electron tube for transferring oscillations for selectively fixing the operating potential ing said piezo electric crystal-element in a shunt with said grid and cathode electrodes or in shunt with said grid'and plate electrodes, said circuits being arranged for sus- 'taining the oscillations of said piezo electric crystal element, an independent electrontube system having its input" circuit connected in parallel with the input circuit of said'first mentioned electron tube andinde endent circuits connected in shunt with eac of said in put circuits for fixing the operating potential of the grid electrodes ofeach of said electron tubes Whereby the oscillations of said piezoelectric crystal element may be transferred to said independent electron tube system while preventing reactionary efiects of the'oscillatiofns said independent electron tube system upon said piezo electric crystal element. v

f ;3. 'A piezo electric crystal control system, comprising an electron qtube having grid,

cathode andplate electrodes, input andoutput circuits interconnecting said'electrodes, a

piezoelectric crystal element, means for con shunt with said grid and'plate electrodes or in shu'nt with said grid and cathode electrodes, said circuits being arranged for sus- 'tainingoscillations corresponding in fre quency totheoscillations ofsaid piezo electric crystal element an independentelectron tube system including'input and output cirunits with the inputcircuitof-said inde pendent electronl tube system connected in k parallel with the input circuit of'said'firs t mentioned electrontube, separate sources of potential 1 having their negative terminals connected to thegrid electrodes of each of said electron tubes for adjusting the operating lpotenital; thereof said 61601 194 tub y lac tem operating to sustainthe oscillations of said piezo electric crystal element while preventing reactionary efl'ects of said oscillations upon said piezo electric crystal element. 3 4. A piezo electric crystal control system, comprising an electron tube having grid, cathode and plate electrodes, input and out put circuits interconnecting said electrodes, a piezo electric crystal element connected with said circuits, said circuits operating to sustain oscillations corresponding in frequency to oscillations of said piezo electric element, 7 an independent electron tube system including grid, cathode and plate electrodes with the grid electrode connected with'the grid electrode of said first mentioned electron tube and cathode electrode thereof connected with the cathode electrode of said first mentioned electron tube and separate circuits in- 29 eluding a biasing battery and a variable resistor bridging each of said input circuits for I regulating the operating potential of the grid electrodes of each of said tubes whereby oscillationsdeveloped by said piezo electric element may be transferred to said electron tube system and the reactionary effects of the oscillations upon said circuits substantially eliminated. c

In testimony whereof I affix my signature.

' 30 r AUGUST HUND. 

